The study on the local structure of steady solutions has also attracted recent attention, see [1]}, [2]}, [3]}, [4]}. The domain in which the motion takes place actually plays an important role in the structure of the stationary solutions and its properties. For example, Hamel and Nadirashvili proved that in a strip where the velocity has no stagnation points, the flow must be shear, see [5]} and the references therein for this and similar results in the half-plane and radial domains. This rigidity confers the idea that certain steady solutions adapt to the geometry and symmetries of the domain they occupy. Further results in this direction are given in [6]}, [7]}.
